A printing plate material for CTP capable of recording digital data employing a laser beam is required to be more highly light-sensitive for the purpose of carrying out recording in a short time. Further, a printing plate having high printing durability has been desired in various printing fields such as newspaper printing and commercial printing.
In order to obtain high sensitivity, an attempt to employ a photo-radical polymerization has been made, and a method employing, as a photopolymerization initiator, a trichloromethyl group-containing s-triazine compound has been proposed in Japanese Patent O.P.I. Publication Nos. 48-36281, 54-74887, and 64-35548. However, this method results in poor sensitivity.
A method employing, as a photopolymerization initiator, a combination of an iron-arene complex and a peroxide has been proposed in Japanese Patent O.P.I. Publication No. 59-219307, a method employing, as a photopolymerization initiator, a monoalkyltriaryl borate compound in Japanese Patent O.P.I. Publication Nos. 62-150242, 62-143044, and 64-35548, and a method employing, as a photopolymerization initiator, a titanocene compound in Japanese Patent O.P.I. Publication Nos. 63-41483 and 2-291. However, these methods also result in poor sensitivity.
Further, a method employing a combination of a monomer (an addition polymerizable ethylenically unsaturated monomer) having a tertiary amine and a trihalogenomethyl group-containing s-triazine compound has been proposed in Japanese Patent O.P.I. Publication No. 1-105238, and a method employing a combination of a monomer (an addition polymerizable ethylenically unsaturated monomer) having a tertiary amine, a trihalogenomethyl group-containing s-triazine compound and a metallocene compound such as titanocene has been proposed in Japanese Patent O.P.I. Publication No. 2-127404. These methods exhibit improved sensitivity, but poor printing durability.
Proposal employing a combination of titanocene and an oxadiazole compound having one halogenomethyl group has been made (see Japanese Patent O.P.I. Publication Nos. 2001-66773), however, this method has problem in that sensitivity and storage stability are poor.